Gas generation in both Li-ion and lithium-metal based primary and secondary electrochemical cells may become a serious problem both during normal cell operation at room temperature and, more especially, at elevated temperatures. The consequence of gas build up includes cell can expansion and subsequent can rupture, leading to cell and or battery failure. For example, the gassing problem has been observed to be extremely serious in large electric vehicle type cell systems and in pouch type cell systems where rupture of the cell containment leads to serious safety problems. The gassing problem is also very serious in lithium-metal based primary cells using liquid and/or solid electrolytes in vivo applications such as for heart pacemakers and similar devices.
Because both the negative and positive electrodes in the charged states of nearly all lithium based electrochemical cell systems are thermodynamically unstable in respect to the electrolyte, it is especially important that electrolyte additives be developed to stabilize the electrodes by decreasing the kinetics of the respective electrode reactions and thereby reducing the gas generation.